1. Field of the Invention
The present invention relates to a board adapted to mount an electronic device, a semiconductor module and a manufacturing method therefor, and a portable device.
2. Description of the Related Art
In recent years, with miniaturization and higher performance in electronic devices, demand has been ever greater for further miniaturization of semiconductor devices used in the electronic devices. With such miniaturization of semiconductor devices, it is of absolute necessity that the pitch of electrodes to enable mounting on a board adapted to mount an electronic device be made narrower. A known method of surface-mounting a semiconductor device is flip-chip mounting in which solder bumps are formed on electrodes of the semiconductor device and the solder bumps are soldered to an electrode pad of the board adapted to mount an electronic device. With this flip-chip method, however, there are restrictive factors for the narrowing of the pitch of electrodes, such as the size of the solder bump itself and the bridge formation at soldering. As one structure used to overcome these limitations, known is a structure where a bump structure formed on a substrate is used as an electrode or a via, and the electrodes of the semiconductor device are connected to the bump structure by mounting the semiconductor device on a substrate by interposing an insulating resin, such as epoxy resin, between the semiconductor device and the substrate.
In a structure having a bump structure provided on electrodes of a packaging board adapted to mount an electronic device and a semiconductor device so mounted on the board that the bump structure and the electrodes of the semiconductor device are connected, known is another structure used to improve the connection reliability between the bump structure and the electrodes of the semiconductor device by coating or covering the electrodes of the board and the bump structure with a metal plating layer.
As described in each of the above-described conventional structures, in the structure where the board and the semiconductor device are stacked together by press-bonding the bump structure provided on the electrodes of the board and the electrodes of the semiconductor device, a stress caused by the change in temperature of its environment is concentrated at the interface between the bump structure and the electrodes of the semiconductor device. As a result, the stress may cause damage to the electrodes of the semiconductor device. The reliability of connection between the bump structure and the electrodes of the semiconductor device drops when the electrodes of the semiconductor device are actually damaged.